This invention is directed to a Surface Acoustic Wave (SAW) device, more particularly to a signal processing device called a convolver. A convolver has an inputs a signal, designated as S and a reference signal designated as R and an output which is the convolution of these two inputs.
The prior art convolvers achieved broad bandwidth by using a periodic transducer (equally spaced electrodes) and limiting the number of electrodes to five or fewer. A matching circuit containing inductors and capacitors was also required in order to achieve 3dB fractional bandwidths approaching 40 percent. Transducers of this type did not allow the flexibility to compensate for amplitude and phase distortions occurring in other parts of the convolver, a feature of the present invention.